Air cargo container, a refrigerator unit for an air-cargo container and a manufacturing method of an air-cargo container

ABSTRACT

The present invention discloses an air-cargo container ( 1 ), which is equipped with a modular refrigerating unit ( 24 ). The refrigerating unit ( 24 ) is attachable into the container shell in substantially one piece. Preferably, a control unit ( 26 ) for the modular refrigerating unit ( 24 ) is also provided as one single module. The refrigerating unit ( 24 ) comprises the entire enclosure of an airflow path around an icebox, and is preferably mounted at a small distance from the wall ( 20 ) and ceiling ( 10 ) of the container ( 1 ). Simple positioning elements facilitate the actual positioning and mounting procedure. The refrigerating unit ( 24 ) preferably comprises sealing flanges which during mounting by the positioning elements automatically are fitted into elements at the container wall ( 20 ). A manufacturing method is also disclosed, which comprises mounting of modular units ( 24, 26 ) into a shell of an air-cargo container ( 1 ). The mounting is preferably performed by using positioning elements, which guides the modular units ( 24, 26 ) into the proper positions.

TECHNICAL FIELD

[0001] The present invention relates generally to air-cargo containersor other ULD:s (Unit Load Devices), and in particular to temperaturecontrolled air-cargo containers/ULD:s and the manufacturing thereof.

BACKGROUND

[0002] The amount of goods transported by airfreight has increasedconsiderably during the last years. In particular, transport oftemperature sensitive goods, such as food, drugs, electronic equipmentetc. has become more important. In order to be able to control thetemperature even during the flight, insulated containers withtemperature regulating equipment have been developed. Since securityregulations concerning airfreight puts severe limitations on which typeof equipment to be used during the flight. Carbon dioxide ice, placed inan icebox, is typically used as refrigerating medium. The icebox coolsdown the surrounding air and by means of small battery-driven fansystems, the cold air may be distributed within the containercompartment.

[0003] In the design of ULD:s in general, such as air-cargo containers,weight is one of the most important parameters. Thus, the manufacturingof containers according to the prior art aims to reduce the amount ofused material as far as possible. The icebox, fan equipment, controlequipment and screens for defining airflow paths are thus attacheddirectly into position in the container. The mounting takes place pieceby piece, and makes use of the container walls and ceiling to reduce thetotal weight.

[0004] When the carbon dioxide ice evaporate, carbon dioxide gas isproduced. This gas has to escape from the icebox. Some goods transportedin cooled containers will be damaged by carbon dioxide exposure, why thecarbon dioxide gas has to escape directly to the exterior of thecontainer, and the icebox is therefore normally placed in the closevicinity of one of the container walls. The icebox also has to be sealedoff from the interior of the container. Such sealing is performeddirectly against the container walls to ensure that no leaks willappear.

[0005] One example of an air-cargo container is disclosed in theinternational patent application WO97/27128 of Frigotainer AB. In orderto increase the temperature interaction between the icebox and thesurrounding air, an airflow path is typically arranged around theicebox, normally by providing flow paths in contact with the icebox. Thetypical configuration is to mount the icebox at a distance from the walland ceiling of the container, using the container shell as the outerconstriction of the flow path. This increases the sealing problems evenfurther.

[0006] Containers according to the prior art have a number ofdisadvantages. First, the mounting times are long, since the difficultand detailed attachment of the numerous details of the cooling equipmenttakes place in a ready container shell. The limited space within thecontainer makes the work difficult, and the total volume of thecontainer requires large available mounting areas. The detailed mountingalso requires skilled personnel and often also special tools, whichmakes end mounting and maintenance difficult at other places than at theproduction plants.

[0007] The distribution of containers from the manufacturing plant tothe customers normally takes place by airfreight. Smaller numbers ofempty containers may be fitted into free space in different transports,but there is no place available for larger amounts. Special freightsthen have to be arranged for the distribution of new empty containers,which increase the total cost.

[0008] There are also some minor technical problems with air-cargocontainers according to prior art. The airflow path around the icebox istypically in direct contact with the container wall. The wall will thusbe cooled at a section where the need of cooling is low, reducing theavailable cooling effect of the carbon dioxide ice. Furthermore, thecooling of the container wall and ceiling at this position may evencause condensation or ice build-up problems at the outside of thecontainer.

[0009] Also, during periods, where no cooling of the containercompartment is not necessary and any fans are shut off to stop theairflow around the icebox, there are problems with cold air flowing downfrom the icebox in the opposite direction than the intended one. Inorder to stop such back-streaming of cold air, the airflow path situatedabove the inlet and outlet openings of the airflow path may be thermallyinsulated in order not to produce any cold air. However, such insulationreduces the available heat exchange between the air and the icebox.

SUMMARY

[0010] An object of the present invention is to facilitate a simplemounting of air-cargo containers and other ULD:s, which is suitable bothfor remote end mounting and service purposes. Another further object ofthe present invention is to improve the heat exchange with the iceboxand to use the cold air in a more efficient manner.

[0011] The above objects are achieved by devices and methods accordingto the present patent claims. In general words, an air-cargo containeris equipped with a modular refrigerating unit, which is attachable intothe container shell in one piece. Preferably, a control unit for themodular refrigerating unit is also provided as one single module. Therefrigerating unit comprises the entire enclosure of an airflow patharound an icebox, and is preferably mounted at a small distance from thewall and ceiling of the container. Simple positioning elementsfacilitates the actual positioning and mounting procedure. Therefrigerating unit preferably comprises sealing flanges which duringmounting by the positioning elements automatically are fitted intoelements at the container wall. Back-streaming of cold air is preventedby letting a flexible sheet cover the inlet opening of the airflow pathby the action of gravity.

[0012] According to another aspect of the invention, a manufacturingmethod is disclosed, which comprises mounting of modular units into ashell of an air-cargo container. The mounting is preferably performed byusing positioning elements, which guides the modular units into theproper positions.

[0013] The present invention has a number of advantages. The modularmounting provides a possibility for remote end mounting of containers.This means that the containers may be distributed in relatively smallcompact packages and can be end mounted at the end user in a simplemanner. Service is facilitated, since defect modules simply areexchanged for new ones, and the actual service will not stop the use ofthe rest of the container. Furthermore, the incorporation of the entireairflow path around the icebox into the refrigerating unit removes someof the previous sealing problems. By furthermore positioning therefrigerating unit properly, the heat transfer to/from the containerwall is reduced.

BRIEF DESCRIPTION OF THE DRAWINGS

[0014] The invention, together with further objects and advantagesthereof, may best be understood by making reference to the followingdescription taken together with the accompanying drawings, in which:

[0015]FIG. 1 is an embodiment of an air-cargo container according to thepresent invention;

[0016]FIG. 2 is a perspective view of an embodiment of a refrigeratingunit according to the present invention, illustrating an airflow patharound an icebox;

[0017]FIG. 3 is a cross-sectional view of a refrigerating unit accordingto the present invention mounted in an air-cargo container;

[0018]FIG. 4 is a detailed view of positioning elements for a preferredembodiment of the refrigerating unit;

[0019]FIG. 5 is a detailed view of another positioning element for apreferred embodiment of the refrigerating unit;

[0020]FIG. 6 is a detailed view of a sealing between the icebox and thewall of the container in a preferred embodiment of the presentinvention;

[0021]FIGS. 7a and 7 b illustrates the inlet portion of a preferredembodiment of the refrigerating unit without and with an inwardsdirected air flow, respectively; and

[0022]FIGS. 8a and 8 b are flow diagrams illustrating manufacturingprocedures according to preferred embodiments of the present invention.

DETAILED DESCRIPTION

[0023] According to the present invention, a temperature controlledair-cargo container is mounted in a modular fashion. A container shellis assembled, which comprises a floor, a ceiling and walls and composesthe main structure of the air-cargo container. In order to providetemperature control, a refrigerating unit is provided, providing astream of cooled air. A control unit, regulating the operation of therefrigerating unit is also provided. Preferably, an icebox lid unit isalso provided. According to the present invention, the refrigeratingunit and preferably also the control unit and icebox lid unit areprovided as modular units, i.e. each of them is mounted in the containershell as one piece or module, including all its functions within thismodule. The respective module is attached to the container shell in theproper position by attachment means, which may be separate from themodules, and is electrically connected. Preferably, this attachment isperformed in an easily detachable manner, in order to facilitate e.g.replacement of the module. The attachment means should therefor allow aneasy removal of said modular unit as an integral whole.

[0024] The mounting of the refrigerating unit and possibly also thecontrol unit as modules implies a number of advantages. The precisionwork of assembling the refrigerating unit can be performed at anotherplace than the final assembling of the entire container. Therefrigerating unit can also be assembled under much more comfortableconditions, than inside a container. The modules may be functionallytested in special test equipment before the final mounting into thecontainer, instead of making the tests on the final container. Thismeans that the time between when the empty container shell is providedand when a complete temperature controlled container is ready isremarkably reduced, which gives cost advantages. Furthermore, the finalassembling may be performed by means of only simple tools, and bynon-specialist workers. The container may even be transported to itsdelivery destination in pieces, and the container shell and the modulemounting may be performed at the final destination. This reduces thetransport costs significantly.

[0025] The modular assembling concept, together with the attachmentmeans allowing for an easy removal, makes service operations very easy.Any defect modules or container shell parts may easily be replaced bynew ones in a very short time, and the use of the container can beresumed. The damaged or defect part or module may then be repairedeither at the field or sent to any service facility, or simply scraped.Also, by applying the assembling concept of the present invention, thecontainer becomes easily collapsible. In other words, the container maybe easily dismounted at one place, transported in a compact manner toanother place, or simply stored in a compact manner, and finallyre-assembled. This is a considerable advantage in cases where the amountof incoming and outgoing temperature sensitive goods is differingconsiderably, and where a pile-up or lack of container units may arise.A redistribution of “collapsed” containers is cheaper and easier thantransportation of empty mounted containers.

[0026] The concept of manufacturing air-cargo containers in a modularway has not earlier been used, despite the fact that such containershave been available since decades. The advantages of module mounting arequite clear, once the idea is presented, but in the present technicalfield, this has not been an obvious step to make. The reason for thismay partly depend on the fact that most air-cargo containers are fairlysimple, and that there are no complicated assembling inside thecontainer shell. In modern temperature controlled air-cargo containers,such as the one disclosed in the international patent applicationWO97/27128, the introduction of refrigerating equipment has increasedthe number of internal parts. However, even here, sealing problems andconcerns about minimising the total weight have drawn the attention toother mounting principles.

[0027] By introducing a modular mounting of the refrigerating unit, someproblems are accentuated. In a refrigerating unit, mounted piece bypiece, the main sealing problem is the one prohibiting the carbondioxide gas to penetrate into the container compartment in connectionwith the icebox lid. However, the individual pieces may easily be sealedagainst the container walls, providing a requested airflow path aroundthe icebox. By introducing a modular refrigerating unit, such sealinghas to be solved together with the attachment of the unit, or within theunit itself.

[0028] A preferred embodiment of the present invention will now bedescribed in detail. In FIG. 1, an air-cargo container 1 is illustrated.The container 1 comprises a container shell, in this embodimentconsisting of a ceiling 10, a floor 12, two end walls 16, 20 and twoside walls 14, 18. One of the end walls 20 provided with a slopingportion 22, according to IATA ULD-standards. One of the side walls alsoprovides an opening with doors (not shown), for access to the interioror compartment of the container 1. According to the present invention, arefrigerating unit 24 is provided as one single module. Therefrigerating unit 24 is mounted in the container compartment in thevicinity of one of the end walls 20 and the ceiling 10. Therefrigerating unit 24 is in this embodiment mounted at a small distanceto the container shell, which will be described more in detail below.The refrigerating unit 24 comprises an icebox opening 28, through whichcarbon dioxide ice may be entered into the refrigerating unit 24. Acorresponding opening 29 is provided in the end wall 20.

[0029] A control unit 26, for regulating the operation of therefrigerating unit 24 is also provided as a module, and is mounted atone of the side walls 12 in the vicinity of the refrigerating unit 24.The control unit 26 is electrically connected to the refrigerating unit24. The control unit 26 is in the present embodiment powered bybatteries (not shown). A temperature sensor 27 is mounted within thecontainer compartment in order to provide the control unit 26 withinformation about the cooling situation in the container. The regulationof the refrigerating unit 24 operation is based on the sensor readings.

[0030]FIG. 2 illustrates the refrigerating unit 24 in somewhat moredetail. Some parts of the refrigerating unit 24 are remove in order tofacilitate the understanding of the drawing. The refrigerating unit 24comprises an icebox 40, in which carbon dioxide ice is going to beplaced for serving as a cooling agent. In this embodiment, therefrigerating unit 24 comprises a totally covered airflow path aroundthe icebox 40 entirely within the module, illustrated by the arrows 30(of which only some has been supplied with reference numbers in order tosimplify the illustration). This means that the interior airflow path isdefined by enclosure means, such as a top plate 32, an outer side plate34, a bottom plate 36 and an inner side plate 38. A closed airflow pathremoves the problems of sealing any airflow path against the containerwalls and ceiling.

[0031] The airflow through the airflow path starts through an inletopening 42, which is described more in detail below. Two deflectionplates 50 distribute the airflow partly to the sides. The airflowcontinues between the icebox 40 and the outer side plate 34 on each sideof the icebox opening 28, and further below the icebox 40 and above thebottom plate 36. The flow continues up between the icebox 40 and theinner side plate 38 and out through two outlet openings 44, 46. Theairflow is prohibited to reach the inlet region by constriction plates48. The airflow path 30 thus encircles substantially the whole icebox40, accomplishing a cooling down of the air.

[0032] The cooled air is passed into the container compartment, incertain embodiments guided by special air distributing means (brieflydiscussed below).

[0033]FIG. 3 illustrates a cross section if the refrigerating unit 24along the arrows A-A in FIG. 2, when mounted in the container 1. Theairflow path is also here easily distinguishable. The incoming air isdrawn by a fan 41 through an inlet frame 82 and the inlet opening 42.The fan is protected from mechanical damage by a grid 76. A valve 58(further discussed below) prohibits backstreaming of cooled air when thefan is not operating. The airflow continues around the icebox 40, andbroken arrows 31 indicate a flow in front or behind the plane of thedrawing. The plates 32, 34, 36 and 38 and the icebox 40 defines theairflow path around the icebox 40. The airflow exits through (not shown)outlet openings above distribution plates 66, arranged at the ceiling 10of the container. The bottom plate 36 and the outer side plate 38 areformed by insulating panels, having an insulating layer 52, to reducethe heat transfer from the container compartment.

[0034] It should be noticed, that the enclosure of the airflow path inthe vicinity of the container shell, i.e. the plates 32 and 34, arepositioned at a small distance 73, 71 from the ceiling 10 and the endwall 20, respectively. This separation reduces the heat transfer betweenthe refrigerating unit 24 and the container shell, which means that thecooling capacity of the carbon dioxide ice is used more efficiently. Inorder to facilitate an easy positioning of the refrigerating unit 24relative to the container shell, positioning elements 68, 70, 74 areprovided. These elements 68, 70, 74 will be further discussed below.

[0035] Around the icebox opening 28, a sealing profile 56 is provided.The profile 56 is attached to the edges of the icebox opening, and is inthis embodiment provided with a cavity, directed towards the end wall20. The cavity is filled with sealing material 84. A sealing flange 60is arranged at the container end wall 20 pointing inwards to the icebox40 through the end wall opening 29.

[0036] The sealing flange 60 has a protruding part, which is conformedwith the cavity of the sealing profile 56. When the protruding part ofthe flange 60 is introduced into the cavity of the profile 56, a sealingis provided. This is described more in detail below.

[0037] An icebox lid 54 is attached by hinges 78 to the end wall 20. Asealing 64 seals off the interior of the icebox 40 from the volumeoutside the container. However, when an overpressure of carbon dioxidegas builds up within the icebox 40, the overpressure of the gas willescape through a hole 55 in the icebox lid 54. A hole may alternativelybe provided in the profile 56. An alternative way is also to let the gaspush away the sealing 64 in order to release some gas. The lid is lockedby a latch 80.

[0038]FIG. 4 illustrates a detailed drawing of the positioning andattachment means between the container end wall 20 and the refrigeratingunit 24. A profile element 68 is attached to the lower edge of therefrigerating unit 24. The profile element is shaped with two legs 67,69 along the refrigerating unit outer walls and a portion 75 protrudingoutwards, substantially in a vertical direction. A profiled strip 70 isattached to the end wall 20 by attachment means, in this embodiment ascrew 72. The profiled strip 70 forms a cavity 77, the opening of whichis directed upwards. The profiled strip 70 also comprises a shoulderportion 79. The protruding portion 75 can be inserted into the cavity77, and the refrigerating unit may be tilted around the tip of theprotruding portion, until the side of the protruding portion 75 comesinto contact with the shoulder portion 79. The profiled strip 70prohibits the profile element 68 to be moved downwards along the endwall 20, and the shoulder portion 79 and the cavity 77 prohibits theprofiled element 68 to be moved any significant distance perpendicularto the end wall 20, when the refrigerating unit 24 is tilted into asubstantially horizontal position. The profiled strip 70 and the profileelement 68 together defines the position of the refrigerating unit 24relative to the end wall 20, in order to provide a suitable separation71.

[0039]FIG. 5 illustrates a detailed drawing of the positioning betweenthe container ceiling 10 and the refrigerating unit 24. A shoulderelement 74 is provided at the upper part of the refrigerating unit 24,in this embodiment in connection with the inlet opening, enclosing theairflow path. The width of the shoulder element 74 defines the distancebetween the upper plate 32 and the inner surface of the containerceiling 10.

[0040] When mounting the refrigerating unit 24, the refrigerating unit24 is tilted somewhat and the profile element 68 is entered into thecavity 77 of the profiled strip 70. The whole refrigerating unit 24 isthereafter tilted back to a substantially horizontal position, until theshoulder element 74 comes into contact with the ceiling 10. Thepositioning elements 68, 70, 74 are easy to manufacture to give apositioning accuracy of the requested degree. The refrigerating unit 24is thereafter fixed to the container shell, preferably by attachingangle plates (not shown) to the side walls of the container. The angleplates may preferably be fastened by a limited number of screws orrivets, which makes a dismounting relatively easy. By making therefrigerating unit 24 easy to remove, facilitates any replacementoperations, which is important for providing a fast maintenance service.Other easily detachable attachment means according to known art may alsobe used.

[0041] As anyone skilled in the art understands, there are many possiblevariations and modifications of suitable positioning means. The profileelement 68 may have a different profile, and the actual shape of theprofiled strip 70 may also be altered, as long as they provide apossibility to tilt the profile element 68 around the tip of theprotruding portion without having any possibility to be moved downwardsalong the end wall 20, i.e. providing a hinging relation. The profileelement 68 may be extended along the entire length of the refrigeratingunit edge, but may also be provided as shorter portions. The samereasoning is valid for the profiled strip 70. However, the mechanicalstrength of the attachment elements has to be designed for the expectedforces during transportation and loading, why continuous strips andprofiles are preferred.

[0042] The mounting procedure is briefly described in FIGS. 8a and 8 b.The manufacturing process starts in step 100. In step 102, arefrigerator unit is provided, by assembling the refrigerator unit inone module. The control unit is in a similar way assembled and providedin step 104. In step 106, the container shell, comprising e.g. floor,ceiling and walls, is assembled. In step 108, the modules are mountedinto the container shell, before the process is completed in step 118.

[0043]FIG. 8b describes a preferred manner to accomplish the mountingstep 108 in FIG. 8a in more detail. In step 110, a profile element ofthe refrigerating unit is inserted into a cavity of a profiled strip.The refrigerating unit is tilted into its required position in step 112,and is subsequently fixed against the container shell in step 114. Instep 116, the control unit is mounted and connected to the refrigeratingunit and the icebox lid unit is mounted. The procedure then continues tothe step 118, where the manufacturing is ended.

[0044]FIG. 6 illustrates a detail around sealing of the icebox opening.Some details, which are not of interest for this aspect, are removedfrom the illustration. The edge of the icebox opening 28 is covered witha plastic sealing profile element 56, which is attached to the enclosure41 of the icebox 40 and to the outer part 43 of the refrigerating unit24. The sealing profile element 56 is provided with a cavity 83, theopening of which is directed towards the end wall opening 29. The cavity83 is partly filled with a sealing material 84, preferably either glueor silicon. The opening 29 in the end wall 20 is surrounded by anothersealing profile, in this case a flanged plate 60. The inner part of theflanged plate is a protruding flange 61, protruding inwards to theinterior of the container. The protruding flange 61 has the same shapeas the cavity 83 of the profile 56, i.e. is conformed with the cavity.The protruding flange 61 has a length, which is adjusted to reach almostto the bottom of the cavity 83 when the refrigerating unit 24 and theprotruding flange 61 are positioned in their final positions. Since thecavity 83 has a slightly wider opening than bottom, the protrudingflange 61 will be guided into the cavity upon mounting. The width anddepth of the cavity 83 allows for accommodate construction tolerances inthree dimensions of the different parts. Preferably, the refrigeratingunit is first tilted into its final position, the cavity 83 is filledwith the sealing material 84, and the icebox lid 54 is thereafter fittedinto its position, thereby forming a sealing by interaction with thesealing material 84 and the cavity 83. This sealing efficientlyprohibits the carbon dioxide gas to penetrate into the containercompartment.

[0045] Different variations and modifications are possible. The cavitypart of the sealing, with the sealing material can be provided at theend wall 20 instead, and the icebox opening may then be provided with aprotruding flange. Other shapes may also be possible, as long as theyare conformed in the plane of the openings, and that one part of one ofthe sealing flanges is possible to fit into a generally cavity shapedpart of the other one.

[0046] In the preferred embodiment, the refrigerating unit 24 is alsoprovide with a valve prohibiting backstreaming of cold air, when the fanin inactive. FIGS. 7a and 7 b illustrates the inlet frame 82 in asituation where it is inactive and where the fan blows air into therefrigerating unit, respectively. The inlet frame 82 defines a flow pathof the incoming air, and the air enters into the actual enclosed airflowpath through the inlet opening 42. The inlet opening 42 is directedsomewhat upwards. When the fan is shut off, a sheet 58 of a flexiblematerial, such as rubber or plastics, covers the inlet opening. Thesheet 58 is thereby held against the opening 42 by means ofgravitational forces, such as illustrated in FIG. 7a. When the fan isactive and blows air into the airflow path, the sheet 58 is bent anduncovers the opening 42, whereby the air may enter into the airflowpath.

[0047] It will be understood by those skilled in the art that variousmodifications and changes may be made to the present invention withoutdeparture from the scope thereof, which is defined by the appendedclaims.

1. An air-cargo container or other unit load device, comprising: acontainer shell, having a floor (12), ceiling (10), side walls (14, 18)and end walls (16, 20); a refrigerator unit (24), having an ice box (40)and providing cooled air to the interior of said container shell, saidrefrigerator unit (24) being attached against a first of said end walls(20) and said ceiling (10), said refrigerator unit (24) being providedas a modular unit; a control unit (26), controlling said refrigeratorunit (24); and an icebox lid unit (54, 60, 78), characterised in thatsaid refrigerator unit (24) comprises an enclosure (32, 34, 36, 38),defining an interior air flow path (30) surrounding said ice box (40).2. The air-cargo container according to claim 1, characterised byattachment means, allowing an easy removal of said modular unit in onepiece.
 3. The air-cargo container according to claim 1 or 2,characterised by positioning elements (68, 70, 74), separating saidenclosure (32, 34, 36, 38) from said container shell by a distance (71,73).
 4. The air-cargo container according to claim 3, characterised inthat at least a first of said positioning elements is a profile element(68) protruding outwards in the vicinity of a lower edge of saidrefrigerator unit (24) facing said first end wall (20), and at least asecond of said positioning elements is a profiled strip (70) attachedsubstantially horizontally at said first end wall (20), said profiledstrip (70) forming a cavity (77) with an upwards directed opening, inwhich the protruding part (75) of said profile element (68) can berotatably positioned, whereby said profiled strip (70) prohibits motionof said profile element (68) downwards along said first end wall (20).5. The air-cargo container according to claim 4, characterised in thatat least a third of said positioning elements is a shoulder element (74)attached on the upper part of said refrigerator unit (24), facing aceiling (10) of said container shell, said shoulder element (74)defining the distance (73) between said refrigerator unit (24) and saidcontainer ceiling (10).
 6. The air-cargo container according to any ofthe claims 1 to 3, characterised in that said interior air flow path(30) has an inlet opening (42), directed substantially upwards, saidinlet opening (42) is provided with a back stream valve formed by asheet of a flexible material (58) covering said inlet opening (42),whereby the gravity force keeps said inlet opening (42) closed, when noinwards directed flow is present through the inlet opening (42).
 7. Theair-cargo container according to any of the claims 1 to 6, characterisedin that said refrigerator unit (24) further comprises an ice box opening(28) for access to the interior of said ice box (40), facing said firstend wall (20), and a sealing profile (56) encircling said ice boxopening (28), said first end wall (20) is provided with a wall opening(29), in agreement with said ice box opening, and a sealing profile (60)encircling said wall opening (29), conformed with the sealing profile(56) of said refrigerator unit (24), a first one of said sealingprofiles exhibits a protruding flange (61) in the direction of thesecond one of said sealing profiles, said second one of said sealingprofiles exhibiting a cavity (83), conformed with said protruding flange(61) and filled with sealing material (84), whereby said protrudingflange (61) protrudes into said cavity (67) in contact with said sealingmaterial (84), forming a sealing.
 8. A refrigerator unit (24) for anair-cargo container (1) or other unit load device, said refrigerator(24) unit comprising an ice box (40) and providing cooled air into thesurroundings, said refrigerator unit (24) being provided as a modularunit, characterised by an enclosure (32, 34, 36, 38), defining aninterior air flow path (30), surrounding said ice box (40).
 9. Therefrigerator unit to claim 8, characterised by attachment means,allowing an easy removal of said modular unit in one piece.
 10. Therefrigerator unit according to claim 8 or 9, characterised bypositioning elements (68, 70, 74), separating said enclosure (32, 34,36, 38) from adjacent surfaces by a distance (71, 73).
 11. Therefrigerator unit according to claim 10, characterised in that at leasta first of said positioning elements is a profile element (68)protruding outwards in the vicinity of a lower edge of said refrigeratorunit (24).
 12. The refrigerator unit according to claim 11,characterised in that at least a second of said positioning elements isa shoulder element (74) attached on the upper part of said refrigeratorunit (24), facing upwards, said shoulder element (74) defining thedistance (73) between said refrigerator unit (24) and any surface above.13. The refrigerator unit according to any of the claims 8 to 12,characterised in that said interior air flow path (30) has an inletopening (42), directed substantially upwards, said inlet opening (42) isprovided with a back stream valve formed by a sheet of a flexiblematerial (58) covering said inlet opening (42), whereby the gravityforce keeps said inlet opening (42) closed, when no inwards directedflow is present through the inlet opening (42).
 14. The refrigeratorunit according to any of the claims 8 to 13, characterised by an ice boxopening (28) for access to the interior of said ice box (40), and asealing profile encircling said ice box opening (28), said sealingprofile exhibiting a protruding flange directed outwards from saidrefrigerator unit.
 15. The refrigerator unit according to any of theclaims 8 to 13, characterised by an ice box opening (28) for access tothe interior of said ice box (40), and a sealing profile (56) encirclingsaid ice box opening (28), said sealing profile (56) exhibiting a cavity(83) filled with sealing material (84).
 16. Manufacturing method of anair-cargo container (1) or other unit load device, comprising the stepsof: assembling a container shell, having a floor (12), ceiling (10),side walls (14, 18) and end walls (16, 20); providing a refrigeratorunit (24), having an ice box (40), in turn comprising the step ofattaching a modular refrigerator unit (24) to a first one of said endwalls (20), providing an ice-box lid unit (54, 60, 78), and providing acontrol unit (26), controlling said refrigerator unit (24),characterised in that said step of providing a refrigerator unit (24) inturn comprises the steps of: providing a modular refrigerator unit (24),having an enclosure (32, 34, 36, 38) defining an interior air flow path(30) surrounding said ice box (40), positioning of said modularrefrigerator unit (24) with a distance (71, 73) between said enclosure(32, 34, 36, 38) and said container shell, and fixing said modularrefrigerator unit (24) to said container shell.
 17. The manufacturingmethod according to claim 16, characterised in that said step ofproviding a control unit (26) comprises the step of attaching a modularcontrol unit (26) to a wall (18) of said container shell.
 18. Themanufacturing method according to claim 16 or 17, characterised in thatsaid step of positioning in turn comprises the steps of: inserting aprofile element (68), attached in the vicinity of a lower edge of saidrefrigerator unit (24) and protruding outwards from said refrigeratorunit (24), into a cavity (77), formed by a profiled strip (70) attachedsubstantially horizontally at said first end wall (20), and tilting saidrefrigerator unit (24) around said profile element (68) into therequested position.
 19. The manufacturing method according to claim 18,characterised in that said step of tilting comprises tilting of saidrefrigerator unit (24) until a shoulder element (74) attached on theupper part of said refrigerator unit (24) comes into mechanical contactwith the said container ceiling (10).
 20. The manufacturing methodaccording to any of the claims 16 to 19, characterised in that said stepof providing a modular refrigerator unit (24) comprises the steps of:providing a modular refrigerator unit (24) having an ice box opening(28) and a sealing profile (56) encircling said ice box opening (28),providing said first end wall (20) with a wall opening (29), inagreement with said ice box opening (28), and a sealing profile (60)encircling said wall opening (29), conformed with the sealing profile(56) of said modular refrigerator unit (24), filling sealing material(84) into a cavity (83) in one of said sealing profiles (56), andinserting said sealing profiles (56, 60) into each other, whereby saidsealing material (84) forms a sealing.